Stent systems can be widely used in the treatment of stenoses. For example, intravascular stents can be used in coronary, renal, and carotid arteries to maintain an open passage through the artery. The intravascular stent can be positioned in a clogged artery, for example, by a catheter and set in place by inflating a balloon upon which the stent is mounted. Inflating the balloon expands the diameter of the stent and opens the previously clogged artery. The balloon can then be deflated and removed from the patient while the stent retains an open passage through the artery.
In some instances a vessel can be bifurcated, i.e., a side branch passage is connected to the vessel, at the treatment site. Despite efforts to use a stent at such bifurcations, the sites can be inadequately treated by a stent due to improper placement and subsequent obstruction of the side branch passage.
In delivering a stent to a vessel location, many current devices rely on either passive torque (e.g., pushing the stent forward and allowing the stent that is fixed on the guidewire/balloon to passively rotate itself into place) or creating torque from outside of the patient to properly orient the medical device in the passage.
Unfortunately, such devices often require a significant portion of the catheter assembly, in addition to the balloon, to be subjected to torque in order to align the stent. Also, stent delivery systems for deployment of one or more stent bodies at or around a vessel bifurcation can have difficulties aligning a stent relative to the side branch at the bifurcation of the primary and secondary passages. Subjecting the catheter as well as a vessel to such extraneous torque can cause damage to the stent, the delivery system, and/or the vessel itself.